Retired Marine Col. Lee Busby said Tuesday that despite being a registered Republican, he was never inclined to vote for former Alabama Chief Justice Roy Moore in the Senate race.

“I do normally vote as a Republican, and I am registered as a Republican,” Mr. Busby said on MSNBC.

Mr. Busby, a former aide to John Kelly who is now President Trump’s chief of staff, is running as an independent candidate for the Alabama Senate seat vacated by Jeff Sessions when he became the attorney general. Several women accused Mr. Moore of sexual misconduct when they were teenage girls and he was in his 30s.

Mr. Moore has denied these allegations and vowed to stay in the race.

Republicans fear losing the seat to Democratic candidate Doug Jones and debated launching a write-in candidate, but Mr. Busby said he sees a path to victory as an independent.

“I’m not happy with the two choices I have. And I normally don’t have as an extreme reaction to not being happy with choices. But I felt like there was a lot of people in Alabama who felt like me,” Mr. Busby said.

He added that he calculated the race will come down to about 200,000 votes, which he thinks he can win.